The present invention involves improved methods for using the element indium, in the water soluble compound indium sulfate, as a nutritional supplement. Indium is element number 49 in the periodic table of elements. Indium is a "trace element" as it occurs in tiny amounts in nature. It is found in the earth's crust in 0.05 parts per million. The Merck Index (Twelfth Edition) lists eleven indium compounds, nine have industrial uses, but there is no use (nutritional or medical or other) listed for indium sulfate. The Merck Index lists the indium compounds of indium antimonide, indium arsenide, indium gallium aluminum phosphide, indium phosphide, indium selenide, indium telluride, as being used in semiconductors and indium oxide and indium trichloride, as used for other industrial products. However, no indium compound is indicated as being used in a nutritional product.
The term indium, as used hereafter, means elemental indium and its FDA GRAS (Generally Accepted As Safe) compounds. The inventor is not aware of any scientific studies of the effect of indium, used as a nutritional supplement, on people. Indium always occurs in nature as a compound. The only indium compound presently on the FDA "GRAS" (Generally Accepted As Safe) list is indium sulfate.
The present inventor has discovered that indium as a nutritional supplement presents unusual difficulties because of the problem of its non-absorption. Generally nutritional supplements are taken in pill or liquid form. They may be taken at any time of the day and may be taken with food at mealtimes. However, indium sulfate (and it is believed any GRAS approved indium compounds) are poorly absorbed when taken orally.
A scientific study of the effect of indium on animals is an early work by Dr. Henry Schroeder, who is famous for his work on removing lead from gasoline. He studied seven trace elements and their toxic effect on mice (not humans); Schroeder et al, J.Nutrition, Vol. 101: 1431-1438 (1971); and Schroeder and Nason, J.Nutrition, "Interactions of Trace Metals in Mouse and Rat Tissues; Zinc, Chromium, Copper and Manganese With 13 Other Elements." He concluded that "Indium is not carcinogenic" and it is "relatively not toxic orally". (Schroeder and Mitchener at pages 1435,1436). There is no indication that Dr. Schroeder recognized any health benefits for mice, or for humans, from using indium as a nutritional supplement or that he used indium sulfate in his experiments on mice.
Cooley U.S. Pat. No. 3,937,806 is entitled "Oral Composition For Caries Prophylaxes" and relates to "dentifrices and mouthwashes." They are not swallowed, i.e., "is not intentionally ingested" (col. 1, line 26). It discloses the combination of a "water-soluble fluoride salt and indium-malic acid water soluble complex" (col. 2, lines 22,23). Indium sulfate is not used in the examples. Indium occurs, in trace amounts, in some foods, Zhang et al, "The nutritional components of Actinidia" Chem. Abstracts, Vol. 116, No. 37, 847 (1992) which refers to A. Kolomita--(Kiwi fruit) and mentions "Indium, biological studies 7664-41-7", which is a number referring to a Chemical Abstract and is not the amount of indium in Kiwi fruit.